Rampant groundwater pumping has altered Earth's spin: Study
What's the story
Between 1993 and 2010, humans pumped out so much groundwater that it changed Earth's tilt by 31.5 inches, according to new research. Displacing large quantities of water affects Earth's axis, on which the planet spins. During those years, the study estimates that humans extracted 2,150 gigatons of groundwater. For reference, this amount would cause the global sea level to rise by 0.24 inches.
Study
Water affects Earth's rotational pole
From 2016, researchers have known that water affects the planet's rotational pole. However, this study has revealed how displacing an enormous amount of water affects the planet's tilt. "The distribution of water on the planet affects how mass is distributed," as per the researchers. However, the "specific contribution of groundwater to these rotational changes" wasn't clear until the current study.
Information
'Redistribution of groundwater significantly impacts drift of the rotational pole'
"Earth's rotational pole actually changes a lot," said Ki-Weon Seo, a geophysicist at Seoul National University who led the study. "Our study shows that among climate-related causes, the redistribution of groundwater actually has the largest impact on the drift of the rotational pole."
Measurements
Without considering groundwater, the model was off by 31 inches
In the study, researchers modeled the observed changes in the shift of Earth's rotational pole corresponding to the movement of water. First, the modeling was done with only ice sheets and glaciers, and then groundwater was taken into account. Only when researchers included 2,150 gigatons of pumped-out groundwater, did their model match with observations. Without that, the model was off by 31 inches.
Information
Water pumped from midlatitudes had bigger impact on Earth's tilt
How much groundwater causes a shift in Earth's rotational pole depends on where it is located on the planet. The study found that water removed from the midlatitudes had a bigger impact on Earth's tilt.
Future
Earth's rotational pole normally changes by several meters a year
In general, Earth's rotational pole shifts by several meters every year. The planet's tilt is known to have an effect on the seasons we experience on Earth. Scientists are now contemplating if the changes to the planet's rotational pole could affect climate change in the future. That's something researchers could focus on in the next phase of the study.